Comprehensive visualization of detonation-diffraction structures and sizes in unstable and stable mixtures

Yuto Nagura, Jiro Kasahara, Yuta Sugiyama, Akiko Matsuo

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The geometry and characteristic length of diffraction and re-initiation during a two-dimensional detonation propagation were revealed by visualization. C2H4 + 3O2 (unstable), 2C2H 2 + 5O2 + 7Ar (stable) and 2C2H2 + 5O2 + 21Ar (stable) were used as the test mixtures. Experiments were performed over the deviation angle range from 30°to 150°and the initial pressure range from 15.8 to 102.3 kPa. By self-emitting photography, we confirmed that the geometry and the characteristic length of diffraction are not different among test gases, with the exception of the fan-like structure of re-initiation that occurred regardless of whether the mixture was unstable or stable. We conducted a compensative experiment by changing the deviation angle and initial pressure, and summarized the detonation diffraction by shadowgraph. At deviation angles larger than 60°, we measured the distances from the vertex of the channel corner to the point where the transverse detonation wave reflected on the under wall (= wall reflection distance) and confirmed that wall reflection distances are approximately in the range of 10-15 times the cell width, whether the mixture is unstable or stable.

Original languageEnglish
Pages (from-to)1949-1956
Number of pages8
JournalProceedings of the Combustion Institute
Volume34
Issue number2
DOIs
Publication statusPublished - 2013

Keywords

  • Activation energy
  • Detonation diffraction
  • Detonation initiation
  • Visualization

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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